package com.czk.durant.springframework.core.io;

import cn.hutool.core.lang.Assert;
import com.czk.durant.springframework.utils.ClassUtils;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;

/**
 * 实现是用于通过 ClassLoader 读取 ClassPath 下的文件信息
 *
 * @Author:ChenZhangKun
 * @Date: 2021/6/21 9:21
 */
public class ClassPathResource implements Resource {
    private final String path;
    private ClassLoader classLoader;

    public ClassPathResource(String path) {
        this(path, (ClassLoader) null);
    }

    public ClassPathResource(String path, ClassLoader classLoader) {
        // 断言
        Assert.notNull(path, "path must not be null");
        this.path = path;
        this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());

    }

    @Override
    public InputStream getInputStream() throws IOException {
        InputStream inputStream = classLoader.getResourceAsStream(path);
        if (inputStream == null) {
            if (classLoader != null) {
                throw new FileNotFoundException(
                        this.path + " cannot be opened because it does not exist");
            }
        }
        return inputStream;
    }
}
